<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <title>位移加位移</title>
  <link rel="icon" href="https://img.kaikeba.com/kkb_portal_icon.ico">
  <style>
    body {
      margin: 0;
      overflow: hidden
    }
  </style>
</head>

<body>
  <canvas id="canvas"></canvas>
  <script id="vertexShader" type="x-shader/x-vertex">
    attribute vec4 a_Position;
    //列主序
    uniform mat4 u_Matrix;
    void main(){
      gl_Position = u_Matrix*a_Position;
    }
  </script>
  <script id="fragmentShader" type="x-shader/x-fragment">
    void main(){
      gl_FragColor=vec4(1.0,1.0,0.0,1.0);
    }
  </script>
  <script type="module">
    import { initShaders } from '../jsm/Utils.js';
    import { Matrix4 } from 'https://unpkg.com/three/build/three.module.js';

    const canvas = document.getElementById('canvas');
    canvas.width = window.innerWidth;
    canvas.height = window.innerHeight;
    const gl = canvas.getContext('webgl');

    const vsSource = document.getElementById('vertexShader').innerText;
    const fsSource = document.getElementById('fragmentShader').innerText;
    initShaders(gl, vsSource, fsSource);

    const vertices = new Float32Array([
      0.0, 0.1,
      -0.1, -0.1,
      0.1, -0.1
    ])

    const vertexBuffer = gl.createBuffer();
    gl.bindBuffer(gl.ARRAY_BUFFER, vertexBuffer);
    gl.bufferData(gl.ARRAY_BUFFER, vertices, gl.STATIC_DRAW);
    const a_Position = gl.getAttribLocation(gl.program, 'a_Position');
    gl.vertexAttribPointer(a_Position, 2, gl.FLOAT, false, 0, 0);
    gl.enableVertexAttribArray(a_Position);

    const u_Matrix = gl.getUniformLocation(gl.program, 'u_Matrix')
    const [bx, by] = [0.2, 0.3]
    const [cx, cy] = [0.1, 0.1]
    const bm = new Matrix4().set(
      1, 0, 0, bx,
      0, 1, 0, by,
      0, 0, 1, 0,
      0, 0, 0, 1
    )
    const cm = new Matrix4().set(
      1, 0, 0, cx,
      0, 1, 0, cy,
      0, 0, 1, 0,
      0, 0, 0, 1
    )
    const dm = cm.multiply(bm)
    gl.uniformMatrix4fv(u_Matrix, false, dm.elements)


    gl.clearColor(0.0, 0.0, 0.0, 1.0);
    gl.clear(gl.COLOR_BUFFER_BIT);

    gl.drawArrays(gl.TRIANGLES, 0, 3);



  </script>
</body>

</html>